Term
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Definition
| calcium sulfate dihydrate |
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Term
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Definition
| calcium sulfate hemihydrate |
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Term
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Definition
| heat process performed to create the hemihydrate form of the product (gypsum) |
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Term
| Is calcination reversible? |
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Definition
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Term
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Definition
plaster
stone
high-strength/improved stone
other types: impression plaster, mounting plaster, etc. |
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Term
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Definition
Made by grinding gypsum rock to a fine powder, then heating the powder in an open container to eliminate the water and shatter the crystals
porous, irregular powder particles
referred to as B hemihydrate or type II stone
least expensive and weakest eg: study model, model base, etc.
white
plaster + chemicals = impression plaster (type I) |
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Term
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Definition
made from gypsum through calcination under steam pressure in a closed container
powder particle~ more regular, uniform and less porous
a hemihydrate, type III, or hydrocal eg: diagnostic casts, casts for complete/partial denture construction
various colors |
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Term
| High-Strength/Improved Stone |
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Definition
made from gypsum calcinated in calcium chloride solution
dense, cuboid powder particles w/ reduced surface area
STRONGEST AND MOST EXPENSIVE
type IV stone, die stone,densite, modified a hemihydrate eg: casts/dies for inlay & crown fabrication
newly developed high-strength
stone w/ higher compressive
strength and higher setting
expansion
Type V stone |
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Term
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Definition
plaster of paris
spongy, porous irregular |
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Term
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Definition
dental stone
well formed crystals, dense, more regular |
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